There was an issue with some MIDI interface drivers causing Sonar to stay resident a while ago. Notably for me M-Audio. I thought that was fixed a while ago though. I haven't experienced it since earlyish X3 versions. Which version are you running?

I am running Windows 8.1; X3e build 246.
Maybe piece is corrupt? Ugh
it has 11 midi tracks and 3 audio tracks by the way - so a fair amount going on.
 
Audio firmware..."1.0".  Hmmmm.  That doesn't sound very modern.  If that's not up-to-date, could it be that X3 doesn't behave well with it - they don't mesh well, so to speak?
 
hunkering down out here in NYC area...2 degrees and 21 below with wind chill...back tomorrow AM

I had to get rid of my M audio stuff-besides crashes, it would never disconnect, well not easily from the PC or Sonar.
All went away when M audio went away.
Just a another experience.
 
Also I could not even find FAst track pro listed on M audio support and driver pages--not even under legacy. Of course, my eyesight isn't what it used to be

The fast track line was acquired by avid and they should have drivers and firmware available. Check device manager for any ghosted versions of the ftp and remove them. The presence of them may cause instability.

Thanks guys.  Correct stratman70, I've dug around for updates and it appears the Fast Track Pro has been orphaned.
 
Any recommendations for a replacement?

Try here (scroll down):
http://avid.force.com/pkb/articles/en_US/download/Fast-Track-Pro-Drivers
 
Latest windows driver is 6.1.10
 

sorry for the late reply.  I see that now.  I'm going to give it a shot.  
 
Eric

Splat, Swamptooth and Stratman70,
 
The update to the M Audio FastTrack Pro software and firmware greatly improved the stability.  Weirdly after running it through the paces - that is to say, moving the transport bar around a lot and starting play, it started crashing.  
 
It's almost as if some mysterious cache was getting filled up.
 
When I rebooted the computer, the crashing halted.  Then after playing the tune for awhile, started crashing again, upon transport bar moves and then starts.
 
At this point, wondering if either
1. some settings in preferences should be altered
2. I should give up finally on the M Audio device and get an alternative.
 
Any advice out there, and if I replaced, any suggestions?
 
Thanks

One way to check if the audio drivers are a problem is to uninstall the M-Audio driver and point Sonar at the motherboard's sound card if it has one. It'll mean using the standard Windows drivers and latency will be dreadful, but if Sonar works with that then it points to the M-Audio as a likely suspect.

As for replacing the M-Audio, it really depends on how many inputs/outputs you need and what you want to spend and it's dofficult to suggest anything without knowing that other than saying RME and Focusrite seem generally well regarded.

Well, I would up giving up and yes, I di have the 6110 drivers. But that's just me. I still use my Layla3G. Solid drivers but still a PCI card-so outdated. Never , ever a problem but I wouldn't recommend it due to the age even though it performs flawlessly in win 8.1x64. Depends on the company making the drivers and Echo is\was a great company.
 
My Roland Octa-capture runs very well with no issues on my laptop Win 8.1x64. And that's thru USB 3.0 ports. The quad capture and duo capture are similar, same drivers I believe (don't quote me)
 
Like TLW said depends on your needs. RME is nice but pricey so...........your budget is important.
The Roland's are not pricey and neither is Focusrite.
 
****And my post count is the same as it was on October 5, 2013, amazing bit of forum software we have here.